<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <div id="app">
       {{number | toDouble(3)}}
 
    </div>
    <script src="node_modules/vue/dist/vue.js"></script>
    <script>
        Vue.filter('toDouble', function(value, a) {  //a是传入的参数      
            return value.toFixed(a);
        });
        new Vue({
            el: "#app",
            data: {
                number: 9.2434
            }
        });
    </script>
</body>
</html>